This utility is designed to write a Makefile for an extension module from a Makefile.PL.
It is based on the Makefile.SH model provided by Andy Dougherty and the perl5-porters.

It splits the task of generating the Makefile into several subroutines that can be individually overridden.
Each subroutine returns the text it wishes to have written to the Makefile.

MakeMaker is object oriented.
Each directory below the current directory that contains a Makefile.PL.
Is treated as a separate object.
This makes it possible to write an unlimited number of Makefiles with a single invocation of WriteMakefile().

even if you're not building around a header file, and even if you don't have an XS component.

Run h2xs(1) before you start thinking about writing a module. For so called pm-only modules that consist of *.pm files only, h2xs has the -X switch. This will generate dummy files of all kinds that are useful for the module developer.

The Makefile to be produced may be altered by adding arguments of the form KEY=VALUE. E.g.

perl Makefile.PL PREFIX=/tmp/myperl5

Other interesting targets in the generated Makefile are

make config # to check if the Makefile is up-to-date
make clean # delete local temp files (Makefile gets renamed)
make realclean # delete derived files (including ./blib)
make ci # check in all the files in the MANIFEST file
make dist # see below the Distribution Support section

MakeMaker checks for the existence of a file named test.pl in the current directory and if it exists it adds commands to the test target of the generated Makefile that will execute the script with the proper set of perl -I options.

MakeMaker also checks for any files matching glob("t/*.t"). It will add commands to the test target of the generated Makefile that execute all matching files via the Test::Harness module with the -I switches set correctly.

make alone puts all relevant files into directories that are named by the macros INST_LIB, INST_ARCHLIB, INST_SCRIPT, INST_HTMLLIBDIR, INST_HTMLSCRIPTDIR, INST_MAN1DIR, and INST_MAN3DIR. All these default to something below ./blib if you are not building below the perl source directory. If you are building below the perl source, INST_LIB and INST_ARCHLIB default to ../../lib, and INST_SCRIPT is not defined.

The install target of the generated Makefile copies the files found below each of the INST_* directories to their INSTALL* counterparts. Which counterparts are chosen depends on the setting of INSTALLDIRS according to the following table:

PREFIX and LIB can be used to set several INSTALL* attributes in one go. The quickest way to install a module in a non-standard place might be

perl Makefile.PL LIB=~/lib

This will install the module's architecture-independent files into ~/lib, the architecture-dependent files into ~/lib/$archname/auto.

Another way to specify many INSTALL directories with a single parameter is PREFIX.

perl Makefile.PL PREFIX=~

This will replace the string specified by $Config{prefix} in all $Config{install*} values.

Note, that in both cases the tilde expansion is done by MakeMaker, not by perl by default, nor by make. Conflicts between parameters LIB, PREFIX and the various INSTALL* arguments are resolved so that XXX

If the user has superuser privileges, and is not working on AFS (Andrew File System) or relatives, then the defaults for INSTALLPRIVLIB, INSTALLARCHLIB, INSTALLSCRIPT, etc. will be appropriate, and this incantation will be the best:

perl Makefile.PL; make; make test
make install

make install per default writes some documentation of what has been done into the file $(INSTALLARCHLIB)/perllocal.pod. This feature can be bypassed by calling make pure_install.

An extension that is built with the above steps is ready to use on systems supporting dynamic loading. On systems that do not support dynamic loading, any newly created extension has to be linked together with the available resources. MakeMaker supports the linking process by creating appropriate targets in the Makefile whenever an extension is built. You can invoke the corresponding section of the makefile with

make perl

That produces a new perl binary in the current directory with all extensions linked in that can be found in INST_ARCHLIB , SITELIBEXP, and PERL_ARCHLIB. To do that, MakeMaker writes a new Makefile, on UNIX, this is called Makefile.aperl (may be system dependent). If you want to force the creation of a new perl, it is recommended, that you delete this Makefile.aperl, so the directories are searched-through for linkable libraries again.

The binary can be installed into the directory where perl normally resides on your machine with

In any case you will be prompted with the correct invocation of the inst_perl target that installs the new binary into INSTALLBIN.

make inst_perl per default writes some documentation of what has been done into the file $(INSTALLARCHLIB)/perllocal.pod. This can be bypassed by calling make pure_inst_perl.

Warning: the inst_perl: target will most probably overwrite your existing perl binary. Use with care!

Sometimes you might want to build a statically linked perl although your system supports dynamic loading. In this case you may explicitly set the linktype with the invocation of the Makefile.PL or make:

MakeMaker needs to know, or to guess, where certain things are located. Especially INST_LIB and INST_ARCHLIB (where to put the files during the make(1) run), PERL_LIB and PERL_ARCHLIB (where to read existing modules from), and PERL_INC (header files and libperl*.*).

Extensions may be built either using the contents of the perl source directory tree or from the installed perl library. The recommended way is to build extensions after you have run 'make install' on perl itself. You can do that in any directory on your hard disk that is not below the perl source tree. The support for extensions below the ext directory of the perl distribution is only good for the standard extensions that come with perl.

If an extension is being built below the ext/ directory of the perl source then MakeMaker will set PERL_SRC automatically (e.g., ../..). If PERL_SRC is defined and the extension is recognized as a standard extension, then other variables default to the following:

If an extension is being built away from the perl source then MakeMaker will leave PERL_SRC undefined and default to using the installed copy of the perl library. The other variables default to the following:

If you don't want to keep the defaults for the INSTALL* macros, MakeMaker helps you to minimize the typing needed: the usual relationship between INSTALLPRIVLIB and INSTALLARCHLIB is determined by Configure at perl compilation time. MakeMaker supports the user who sets INSTALLPRIVLIB. If INSTALLPRIVLIB is set, but INSTALLARCHLIB not, then MakeMaker defaults the latter to be the same subdirectory of INSTALLPRIVLIB as Configure decided for the counterparts in %Config , otherwise it defaults to INSTALLPRIVLIB. The same relationship holds for INSTALLSITELIB and INSTALLSITEARCH.

MakeMaker gives you much more freedom than needed to configure internal variables and get different results. It is worth to mention, that make(1) also lets you configure most of the variables that are used in the Makefile. But in the majority of situations this will not be necessary, and should only be done if the author of a package recommends it (or you know what you're doing).

Name of the file that contains the package description. MakeMaker looks for a line in the POD matching /^($package\s-\s)(.*)/. This is typically the first line in the "=head1 NAME" section. $2 becomes the abstract.

Hashref of symbol names for routines to be made available as universal symbols. Each key/value pair consists of the package name and an array of routine names in that package. Used only under AIX, OS/2, VMS and Win32 at present. The routine names supplied will be expanded in the same way as XSUB names are expanded by the XS() macro. Defaults to

This provides an alternate means to specify function names to be exported from the extension. Its value is a reference to an array of function names to be exported by the extension. These names are passed through unaltered to the linker options file.

Hashref of .pm and .pod files. MakeMaker will default this to all .pod and any .pm files that include POD directives. The files listed here will be converted to HTML format and installed as was requested at Configure time.

Hashref of pod-containing files. MakeMaker will default this to all EXE_FILES files that include POD directives. The files listed here will be converted to HTML format and installed as was requested at Configure time.

Array of extension names to be included when doing a static build. MakeMaker will normally build with all of the installed extensions when doing a static build, and that is usually the desired behavior. If INCLUDE_EXT is present then MakeMaker will build only with those extensions which are explicitly mentioned. (e.g. [ qw( Socket POSIX ) ])

It is not necessary to mention DynaLoader or the current extension when filling in INCLUDE_EXT. If the INCLUDE_EXT is mentioned but is empty then only DynaLoader and the current extension will be included in the build.

This attribute may be most useful when specified as a string on the command line: perl Makefile.PL INCLUDE_EXT='POSIX Socket Devel::Peek'

Determines which of the two sets of installation directories to choose: installprivlib and installarchlib versus installsitelib and installsitearch. The first pair is chosen with INSTALLDIRS=perl, the second with INSTALLDIRS=site. Default is site.

Directory, where executable files should be installed during 'make'. Defaults to "./blib/script", just to have a dummy location during testing. make install will copy the files in INST_SCRIPT to INSTALLSCRIPT.

defaults to 0. Should be set to TRUE if the extension can work with the memory allocation routines substituted by the Perl malloc() subsystem. This should be applicable to most extensions with exceptions of those

with bugs in memory allocations which are caught by Perl's malloc();

which interact with the memory allocator in other ways than via malloc(), realloc(), free(), calloc(), sbrk() and brk();

which rely on special alignment which is not provided by Perl's malloc().

NOTE. Negligence to set this flag in any one of loaded extension nullifies many advantages of Perl's malloc(), such as better usage of system resources, error detection, memory usage reporting, catchable failure of memory allocations, etc.

Hashref of pod-containing files. MakeMaker will default this to all EXE_FILES files that include POD directives. The files listed here will be converted to man pages and installed as was requested at Configure time.

Hashref of .pm and .pod files. MakeMaker will default this to all .pod and any .pm files that include POD directives. The files listed here will be converted to man pages and installed as was requested at Configure time.

MakeMaker will figure out if an extension contains linkable code anywhere down the directory tree, and will set this variable accordingly, but you can speed it up a very little bit if you define this boolean variable yourself.

In general, any generated Makefile checks for the current version of MakeMaker and the version the Makefile was built under. If NO_VC is set, the version check is neglected. Do not write this into your Makefile.PL, use it interactively instead.

Ref to hash of files to be processed as perl programs. MakeMaker will default to any found *.PL file (except Makefile.PL) being keys and the basename of the file being the value. E.g.

{'foobar.PL' => 'foobar'}

The *.PL files are expected to produce output to the target files themselves. If multiple files can be generated from the same *.PL file then the value in the hash can be a reference to an array of target file names. E.g.

Ref to array of subdirectories containing library files. Defaults to [ 'lib', $(BASEEXT) ]. The directories will be scanned and any files they contain will be installed in the corresponding location in the library. A libscan() method can be used to alter the behaviour. Defining PM in the Makefile.PL will override PMLIBDIRS.

Release 5.005 grandfathered old global symbol names by providing preprocessor macros for extension source compatibility. As of release 5.6, these preprocessor definitions are not available by default. The POLLUTE flag specifies that the old names should still be defined:

perl Makefile.PL POLLUTE=1

Please inform the module author if this is necessary to successfully install a module under 5.6 or later.

Can be used to set the three INSTALL* attributes in one go (except for probably INSTALLMAN1DIR, if it is not below PREFIX according to %Config). They will have PREFIX as a common directory node and will branch from that node into lib/, lib/ARCHNAME or whatever Configure decided at the build time of your perl (unless you override one of them, of course).

Hashref: Names of modules that need to be available to run this extension (e.g. Fcntl for SDBM_File) are the keys of the hash and the desired version is the value. If the required version number is 0, we only check if any version is installed already.

Arryref. E.g. [qw(name1 name2)] skip (do not write) sections of the Makefile. Caution! Do not use the SKIP attribute for the negligible speedup. It may seriously damage the resulting Makefile. Only use it if you really need it.

Ref to array of typemap file names. Use this when the typemaps are in some directory other than the current directory or when they are not named typemap. The last typemap in the list takes precedence. A typemap in the current directory has highest precedence, even if it isn't listed in TYPEMAPS. The default system typemap has lowest precedence.

Instead of specifying the VERSION in the Makefile.PL you can let MakeMaker parse a file to determine the version number. The parsing routine requires that the file named by VERSION_FROM contains one single line to compute the version number. The first line in the file that contains the regular expression

/([\$*])(([\w\:\']*)\bVERSION)\b.*\=/

will be evaluated with eval() and the value of the named variable after the eval() will be assigned to the VERSION attribute of the MakeMaker object. The following lines will be parsed o.k.:

The file named in VERSION_FROM is not added as a dependency to Makefile. This is not really correct, but it would be a major pain during development to have to rewrite the Makefile for any smallish change in that file. If you want to make sure that the Makefile contains the correct VERSION macro after any change of the file, you would have to do something like

If you specify COMPRESS, then SUFFIX should also be altered, as it is needed to tell make the target file of the compression. Setting DIST_CP to ln can be useful, if you need to preserve the timestamps on your files. DIST_CP can take the values 'cp', which copies the file, 'ln', which links the file, and 'best' which copies symbolic links and links the rest. Default is 'best'.

If you cannot achieve the desired Makefile behaviour by specifying attributes you may define private subroutines in the Makefile.PL. Each subroutines returns the text it wishes to have written to the Makefile. To override a section of the Makefile you can either say:

If you are running experiments with embedding perl as a library into other applications, you might find MakeMaker is not sufficient. You'd better have a look at ExtUtils::Embed which is a collection of utilities for embedding.

If you still need a different solution, try to develop another subroutine that fits your needs and submit the diffs to perl5-porters@perl.org or comp.lang.perl.moderated as appropriate.

MakeMaker.pm uses the architecture specific information from Config.pm. In addition it evaluates architecture specific hints files in a hints/ directory. The hints files are expected to be named like their counterparts in PERL_SRC/hints, but with an .pl file name extension (eg. next_3_2.pl). They are simply evaled by MakeMaker within the WriteMakefile() subroutine, and can be used to execute commands as well as to include special variables. The rules which hintsfile is chosen are the same as in Configure.

The hintsfile is eval()ed immediately after the arguments given to WriteMakefile are stuffed into a hash reference $self but before this reference becomes blessed. So if you want to do the equivalent to override or create an attribute you would say something like

First does a distdir. Then a command $(PREOP) which defaults to a null command, followed by $(TOUNIX), which defaults to a null command under UNIX, and will convert files in distribution directory to UNIX format otherwise. Next it runs tar on that directory into a tarfile and deletes the directory. Finishes with a command $(POSTOP) which defaults to a null command.

First does a distdir. Then a command $(PREOP) which defaults to a null command. Next it runs shar on that directory into a sharfile and deletes the intermediate directory again. Finishes with a command $(POSTOP) which defaults to a null command. Note: For shdist to work properly a shar program that can handle directories is mandatory.

First does a distdir. Then a command $(PREOP) which defaults to a null command. Runs $(ZIP) $(ZIPFLAGS) on that directory into a zipfile. Then deletes that directory. Finishes with a command $(POSTOP) which defaults to a null command.

If some events detected in Makefile.PL imply that there is no way to create the Module, but this is a normal state of things, then you can create a Makefile which does nothing, but succeeds on all the "usual" build targets. To do so, use

ExtUtils::MakeMaker::WriteEmptyMakefile();

instead of WriteMakefile().

This may be useful if other modules expect this module to be built OK, as opposed to work OK (say, this system-dependent module builds in a subdirectory of some other distribution, or is listed as a dependency in a CPAN::Bundle, but the functionality is supported by different means on the current architecture).